This invention relates to improvements in lens surfacing machines. In particular it relates to an improved rocker arm and pin holder assembly especially for use in producing toric lenses.
In a conventional lens polishing machine the lens to be polished is supported on a block and is pressed into contact with the polishing lap by a pair of pins which are engaged in recesses in the lens support block, the pins being carried by a pin holder attached to a rocker arm. Misalignment of the pins out of a horizontal plane which includes the axis of the oscillation of the polishing lap can result in errors in the finished lens, it thus being required that the pins be supported immovably and in extremely accurate alignment in the said axis. The axis of the lens must be kept in line with the axis of the oscillating polishing lap.
In the known constructions, the pin holder is attached to the rocker arm by a single bolt. Bolts carried by lugs on the pin holder are engaged in lateral sides of the rocker arm and are adjusted separately to bring the points of the pins into the required horizontal plane.
A disadvantage of the known construction is that vibration or impact shock can cause movement of the pin holder relatively to the rocker arm with consequential misalignment of the pins.
Therefore the object of the invention is to provide a rocker arm and pin holder assembly for a lens surfacing machine which will maintain an undeviating axis alignment during operation of the machine.
Another object of the invention is to provide a rocker arm and pin holder assembly with means for perfectly aligning the axis.